Contemporary civilization is placing increasing demands on all forms of energy resources and the alarming depletion rate of non-renewable energy sources such as petroleum has placed an increasing demand on development of the relatively inexhaustible energy sources.
One relatively inexhaustible source of energy which has been utilized for ages but has received little interest by those striving to develope new sources of energy is the water pressure head. This source of energy has been used to drive water wheels for generations and the water wheels have been used to grind grain in their crudest form or generate electricity in the more refined turbine. However, the only common, modern use of a water pressure head is in hydroelectric power systems. These systems use enormous quantities of water and provide no useable means to store commercial quantities of the energy produced.
Another means for extracting energy from a hydraulic head which has greater storage potential than the electrohydraulic systems is the conversion of the potential energy into a compressed gas which may be transported over relatively long distances via pipe lines and stored in natural or artificially created subterranean chambers. A few attempts have been made in the past to convert a hydraulic head into compressed gas but these attempts have met with little commercial success for a variety of reasons generally relating to their inability to economically produce a constant commercial volume.
Research has revealed that water from a non-surging head has been used to compress air in commercial quantities. In fact, an Italian engineer, Germain Sommeiller, used a modification of the hydraulic ram to compress air for penumatic drills used in the construction of the Mont Cenis tunnel. This tunnel was built under the Alps (1857-71) and linked the railways of France and Italy. The operation of these devices required huge quantities of water, and the fact that they are no longer in common use as compressors is probably due to their low efficiencies and limited application. The hydraulic ram is still in limited use for lifting water, but its inherent inefficiency and limited application has prevented it from making a substantial contribution. The hydraulic ram is primarily a kinetic energy conversion device. Water from an elevated source is directed through the device until a high velocity flow is attained. By means of a quick-acting valve, the high velocity water exiting the device is stopped. The resultant kinetic kick is utilized to compress air trapped above a water piston, and the greatly intensified compressed air is utilized to drive a small quantity of water to a location much higher than the original source feeding the ram. The design intent of this invention was to overcome the severe inefficiencies and very limited applications of the hydraulic ram. Because of the kinetic shock stresses produced in the hydraulic ram, the construction materials required for even the smallest ram can be very expensive. The intent of the invention hereinafter described is to provide a different approach to the extraction of potential energy from a non-surging head of water, and to make this extraction with much higher efficiencies. A second, and equally important, intent of this invention is to capture economically the energy of water heads with very limited flow volumes.
Some of the early types of utilizing naturally occurring hydraulic heads to compress air relied upon wave and tide motion.
An early example of the use of wave energy to create compressed air is illustrated in U.S. Pat. No. 655,541 issued to A. M. Becker on "Marine Air Power Apparatus" Aug. 7, 1900. In this device, waves rise in chambers having one-way exhaust valves through which air trapped by the wave is forced as the water fills the chamber. A more contemporary example of a similar apparatus is illustrated in U.S. Pat. No. 3,149,776 issued to W. C. Parrish on "Air Compressors Utilizing The Kinetic And Potential Energy Of Water Waves Common To Bodies Of Water" issued Sept. 22, 1964. In this device a deflector or obstructing means causes the waves to build up so that the kinetic energy is converted to potential energy in the form of an increased hydraulic head which forces water into a plurality of tubes containing air which is driven out through one-way valves.
Other examples of pneumatic attempts to harness the hydraulic head created by waves are illustrated in U.S. Pat. No. 567,920 issued to R. Toennes on "Air Compressor" on Feb. 9, 1897; U.S. Pat. No. 960,478 issued to D. R. Allard on "Air Compressor" issued June 7, 1910; U.S. Pat. No. 1,005,911 issued to F. P. Wilbur on "Hydraulic Power Air Compressor" issued Oct. 17, 1911; and U.S. Pat. No. 4,022,549 on "Shore Line Air Compressors Wherein Swell Water Pumps The Air" issued May 10, 1977. All of the foregoing devices are subject to the irregular nature of waves in large bodies of water. Waves of the magnitude required to create compressed air at a commercially acceptable rate are large waves of the kind normally associated with storms and high winds over long reaches of the body of water concerned. These severe environmental situations are not normal and therefore, the operation of compressed air plants relying on wave action is unreliable. Long periods where the body of water is calm due to an absence of storms result in the commercial failure of such systems due to their lack of reliability and lack of a storage system for the compressed air which has a capacity to provide a supply during calm periods.
Other attempts to utilize moving bodies of water to compress air in a more reliable manner rely on tide action. P. H. Montague in U.S. Pat. No. 631,994 on "Air Compressor" issued Aug. 29, 1899 and W. M. Marsden, U.S. Pat. No. 1,036,502 on "System Of Developing Natural Power For Industrial Purposes" issued Aug. 20, 1912 are examples of such devices. Systems such as these failed to meet with commercial success because of the very limited quantity of compressed gas they could produce.
J. O. Boving, U.S. Pat. No. 1,628,025 on "Hydraulic Air Compression Plant" issued May 10, 1927 provides compressed air by relying on any source of moving water which may be caused to flow down a tube. Systems such as Boving utilize a venturi effect to compress the gas and therefore expend large volumes of fluid for a relatively small amount of compressed gas, a feature which apparently renders them commercially unsuccessful.
W. S. Bryant in U.S. Pat. No. 643,863 on "Floating Pump" issued Feb. 20, 1900 disclosed a special case of a pump functioning on wave or tide action in that the compression chambers float upon the body of water creating the required pressure heads. This device suffers from the same shortcomings as previously discussed with respect to wave action and tidal action air compressors.